Colorado law requires no "duty to retreat." If threatened you have the RIGHT to stand your ground. However, my own prinicples recognize that if the lead starts flying - so to speak - I'd rather be snowboarding
In this day and age, there's little that I'm willing to die for and I'll leave if given the opportunity. However, that being said, I'll fight as vicious as a rabid and injured dog if pushed, and I'll take an attacker's life faster than an ex-wife can burn through your bank account.
Any bullet that will penetrate a BG will penetrate car doors, drywall, and common barriers. The .380 and the .40 will penetrate multiple layers of common barriers, so the risk exists with both. However, if I shoot I don't plan to miss... arogant, yes. realistic, no. My goal, yes. So, if I thought I would miss, I wouldn't shoot.